How to judge whether the mouse wheel event scrolls clockwise or counterclockwise? Ask the master to write one in C language! !

It's not written in C, but in C++.

When the message WM_MOUSEWHEEL appears, the wheel rotates.

LRESULT callback WindowProc (

Window handle

UINT uMsg，// WM_MOUSEWHEEL

WPARAM wParam,//key indicator and wheel rotation

LPARAM lParam // horizontal and vertical positions

);

The position of the mouse cursor is x, y.

The position of the roller is actually z, whether it is clockwise or counterclockwise, judging from the position before and after rotation.

z DELTA = GET _ WHEEL _ DELTA _ WPARAM(WPARAM)； //Wheel rotation value